To convey the heavy opener-lap from the opener to the carding room, the more modern mills are doing away rapidly with hand-power, and carry the lap on a sort of travelling mono-rail conveyor. The fibers of the lap which comes from the opening room are by no means parallel, but lie in all directions just as they happened to come from the grid of the opener. The function of the card is to straighten them, and at the same time to remove those which are knotted or immature and of a length below that required for the yarn to be spun, and to take out practically all of the impurities which may have escaped in the opening operations. The principle of carding is one of the oldest of textile mechanical principles, and all the improvements that have been made have been in developments rather than in basic ideas. Hargreaves, inventor of the jenny, and Sir Richard Arkwright both expended their ingenuity upon it, the latter seeming to have been the first to provide a carding machine operated by other than hand-power. The basic principle involved is the straightening out of the fibers by combing or brushing them with wire brushes or cards. [Illustration: _"Scutchers" at work_] In the revolving flat card, which dominates the field today, there are, as a rule, three principal cylinders. The lap passes first under the smallest of the three, called the taker-in, which is covered with very fine saw-teeth all in one long strip of steel, wound and fixed spirally in the surface of the cylinder. The taker-in receives the cotton from a feed-roller (C) that turns above a smooth iron plate (D) called the feed plate. The saw-teeth comb the fibers which are imbedded, so to speak, in the lap, and deliver the loose ones to the second cylinder, which is the largest of the group. This main cylinder is covered with wire teeth all bent at exactly the same angle. The cotton clings to them, and is carried around to the top of the cylinder, where it is engaged by teeth on the revolving-flat card which are bent in the opposite direction. This "card-clothing" arranged in strip, crosswise on a travelling lattice, moves in the same direction as the cylinder but moves very slowly, and so the fibers are carded between the two sets of wire points, the short and immature fibers remaining on the card wires of the lattice and the perfect and now almost entirely parallel ones being carried over from the main cylinder to the doffer cylinder, the third of the trio. From this they are removed by an oscillating comb (F), coming off in a light, fleecy lap, which is condensed through a funnel into a soft untwisted roping, or sliver, about the diameter of a man's thumb, and is then coiled into a can, usually about 45 inches high by 8 inches diameter. [Illustration: _View of Modern Motor-Driven Opener Picker_]